[Prevalence and 5-year mortality of dementia and association with geriatric syndromes in elderly population in Beijing]

Abstract

Objective: To investigate the prevalence and mortality of dementia and assess the impact of geriatric syndromes (GS) on the risk for dementia and death in elderly population in Beijing. Methods: A cross-sectional survey was conducted in the elderly population aged ≥65 years and selected by a multi-stage sampling in Beijing during 2013-2015. Cognitive function was screened using the Chinese Revised Version of the Mini-Mental State Examination (MMSE). Then, neurological examination and psychiatric assessment were performed for those with the MMSE score lower than the cut-off value. The information about GS prevalence was also collected. The study also collected death records for all individuals from baseline until December 31, 2019. Based on the age and gender distribution from Beijing data of the 2010 Six^th National Population Census, the dementia prevalence in the study population was directly standardized. Logistic regression analysis was used to evaluate the association of different forms of dementia with GS, and Cox proportional hazards regression model was used to estimate the hazard ratio (HR) and 95%CI of death. Results: During 2013-2015, a total of 2 935 individuals completed dementia assessments, of which 167 were diagnosed with dementia. The standardized prevalence of dementia was 5.9% (95%CI: 5.0%-17.4%). The individuals with Alzheimer's disease (AD) and vascular dementia (VaD) accounted for 58.7% and 28.1% of total individuals with dementia, respectively. Aging, lower education level, urinary incontinence, and fall were risk factors for AD, while disability of activity of daily life dependence, hypertension, and stroke were found to be risk factors for VaD. After a median follow-up of 5.44 person-years, 399 deaths were recorded. The 5-year mortality risk was 2.87 (95%CI: 1.92-4.17) times and 4.93 (95%CI: 3.23-7.53) times higher for the elderly individuals with AD and VaD, respectively, compared to non-demented individuals. After adjusting for demographic, GS, and cardiovascular risk factors, the mortality risk in the elderly individuals with AD showed no significant difference compared with non-demented individuals (HR=1.32, 95%CI: 0.89-1.97), while the mortality risk in those with VaD was 2.46 (95%CI: 1.49-4.05) times higher than that in non-demented individuals. Conclusions: The prevalence of dementia in Beijing increased significantly in the context of population aging, especially the prevalence of AD. The presence of GS increased the risks for AD and VaD, as well as the risk for death. Close attention needs to be paid to GS management in dementia prevention in elderly population.